MECHANISM OF B-CELL POSITIVE SELECTION IN THE BURSA OF FABRICIUS

法氏囊中的B细胞库通过基因转换而多样化。我们推测，突变的B细胞可能是由来自肠道的相应抗原在法氏囊中原位选择的。在我们的实验中，来自肠道的环境抗原与法氏囊中的母体免疫球蛋白形成了免疫复合物。抗原抗体复合体在法氏囊的髓质中呈树枝状分布。这些结果表明，卵泡树突状细胞(Follicular Dendritic Cells，FDC)捕获的抗原-抗体复合体在法氏囊B细胞的阳性选择中起重要作用。

B-cell repertoire in the bursa of Fabricius is diversified by gene conversion. We speculate that mutated B cells would be selected in the bursa of Fabricius in situ by corresponding antigens derived from the gut. In our experiments, environmental antigens derived from the gut made immune complex with maternal IgG in the bursal follicles. The distribution of antigen-antibody complex showed dendritic appearances in the medulla of bursal follilces. These results suggest that antigen-antibody complex trapped by FDC (Follicular Dendritic Cells), plays an important role in positive selection of B cells in the bursa of Fabricius.